Door damper

ABSTRACT

Disclosed is a door damper, in which a safety check valve is installed in consideration of the case in which an impact exceeding a design pressure will be applied, thereby absorbing the impact to enable a door to be closed safely and smoothly. In the door damper, a safety check valve is installed in a piston, and thus is opened in cooperation with another check valve installed between a spring holder and the piston when the pressure exceeding a design pressure is applied. Thereby, when the impact exceeding the design pressure occurs, the safety check valve can absorb the impact to prevent damage. A channel can be adjusted by only ridges formed on an outer circumference of the check valve, so that productivity can be improved thanks to easy tolerance management. Further, an oil seal is not contracted or deformed in spite of long-term use.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. Section 371, of PCTInternational Application Number PCT/KR2007/004333, filed Sep. 7, 2007,the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a door damper and, more particularly,to a door damper in which a safety check valve is installed inconsideration of the case in which an impact exceeding a design pressurewill be applied, thereby absorbing the impact to enable a door to beclosed safely and smoothly.

BACKGROUND ART

In general, doors are attached to household furniture such as awardrobe, bookcase, etc. or a kitchen cabinet by spring hinges so as tobe able to be easily opened and closed with weak force. When closed, thedoor bumps against a doorframe, so that there is a possibility ofcausing noise or accident.

Particularly, when carelessly abruptly closing the door, a child isinjured in the finger, which is pinched between the doorframe and thedoor.

In order to overcome this problem, a door damper as illustrated in FIG.9 has been developed.

This door damper is designed to use a check valve to rapidly close thedoor by increasing the cross section of a channel through which oil, inan oil chamber, passes when an impact is weak, and to absorb the impactby narrowing the channel cross section when the impact is strong.

DISCLOSURE Technical Problem

Such a door damper has the following problems since the impact isabsorbed only by restricting a flow of the oil using the check valve.

(1) The door damper is easily damaged when the impact exceeding a designpressure occurs.

(2) The door damper is abnormally operated since it is difficult tomanage a tolerance of the check valve.

(3) The oil can leak out since an oil seal is deteriorated with thelapse of time.

Technical Solution

Accordingly, in order to solve the problems occurring in the relatedart, the present invention provides a door damper, which comprises: acylindrical body, which is open on one side thereof, and has a bumper onthe other side thereof; a return spring, which is inserted into thebody; a spring holder, which supports the return spring; a piston, whichis inserted into the spring holder; a check valve, which is installedbetween the spring holder and the piston; a piston rod, which is coupledto one side of the piston, and protrudes outside the body; an oildistributor, which has the piston rod passing therethrough, and is incontact with the piston; a sponge, which is in contact with the oildistributor, has the piston rod passing therethrough, and is fixed to abushing; and a cover, which covers one side of the body together withthe oil seal contacting the bushing. Here, the piston is providedtherein with a safety check valve, which is opened in cooperation withthe check valve installed between the spring holder and the piston whena pressure exceeding a design pressure is applied.

Advantageous Effects

As described above, according to the present invention, the door damperhas the following advantages:

(1) When the impact exceeding the design pressure occurs, the safetycheck valve can absorb the impact to prevent the door damper from beingdamaged.

(2) The channel can be adjusted by only the ridges formed on the outercircumference of the check valve, so that productivity can be improvedthanks to easy tolerance management.

(3) The oil seal is not contracted or leaked in spite of long-term use.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating a door damper according to anexemplary embodiment of the present invention.

FIG. 2 is an exploded perspective view illustrating a door damperaccording to an exemplary embodiment of the present invention.

FIG. 3 is a perspective view illustrating a piston for a door damperaccording to an exemplary embodiment of the present invention.

FIG. 4 is a perspective view illustrating a safety check valve for adoor damper according to an exemplary embodiment of the presentinvention.

FIG. 5 is a perspective view illustrating another safety check valve fora door damper according to an exemplary embodiment of the presentinvention.

FIG. 6 is a perspective view illustrating a check valve for a doordamper according to an exemplary embodiment of the present invention.

FIG. 7 is a perspective view illustrating a spring holder for a doordamper according to an exemplary embodiment of the present invention.

FIG. 8 is a conceptual view illustrating the operation of a door damperaccording to an exemplary embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating a known door damper.

DESCRIPTION OF REFERENCE NUMBERS OF MAIN PARTS IN DRAWINGS

100: body 110: bumper 120: rod 210: return spring 220: piston 230:safety check valve 240: check valve 250: spring holder 310: bushing 320:sponge 330: oil distributor 410: cover 420: oil seal

MODE FOR INVENTION

Referring to FIGS. 1 through 8, a door damper of the present inventioncomprises: a cylindrical body 100, which is open on one side thereof,and has a bumper 110 on the other side thereof; a return spring 210,which is inserted into the body 100; a spring holder 250, which supportsthe return spring 210; a piston 220, which is inserted into the springholder 250; a check valve 240, which is installed between the springholder 250 and the piston 220; a piston rod 120, which is coupled to oneside of the piston 220, and protrudes outside the body; an oildistributor 330, which has the piston rod 120 passing therethrough, andis in contact with the piston 220; a sponge 320, which is in contactwith the oil distributor 330, has the piston rod 120 passingtherethrough, and is fixed to a bushing 310; and a cover 410, whichcovers one side of the body together with the oil seal 420 contactingthe bushing 310. Here, the piston 220 is provided therein with a safetycheck valve 230, which is opened in cooperation with the check valve 240installed between the spring holder 250 and the piston 220 when apressure exceeding a design pressure is applied.

The piston 220 is a cylinder in the middle of which a hole is formed,and is provided with a piston body 221 at an upper portion thereof, anoperating body 222 formed integrally with the piston body 221 and havingan outer diameter less than that of the piston body 221, and aninserting body 223 formed integrally with the operating body 222 andhaving an outer diameter less than that of the operating body 222.

The piston body 221 is provided with a rod inserting hole 221 a at anupper end thereof, which communicates with holes in the operating andinserting bodies 222 and 223 with a diameter difference.

The piston body 221 includes at least one safety channel groove 221 bformed around the rod inserting hole 221 a.

The piston body 221 includes a plurality of channel slots 221 c in anouter circumference thereof, through which oil flows when operated. Thenumber of channel slots 221 c preferably is 4 through 8.

The operating body 222 includes a plurality of projections 222 a, eachof which protrudes from an outer circumference of the operating body 222between two adjacent channel slots 221 c. The number of the projections222 a is smaller than that of channel slots by one.

The safety check valve 230 is inserted into the inserting body 223, andthe spring holder 250 is inserted around the inserting body 223.Thereby, the inserting body 223 and one end of the safety check valve230 are surrounded by the spring holder 250.

The safety check valve 230 is formed of material having strongelasticity, and includes a cylindrical valve body 231, in an outercircumference of which an open slot 231 a is formed in a longitudinaldirection, and an operating head 232 that is formed in a truncated coneshape at one end of the valve body 231.

As in FIG. 5, another example of the safety check valve 230 includes acylindrical body 235, which is integrally formed with one end of theinserting body 223 of the piston 200 and has a hole so as to be able tocommunicate with the hole of the inserting body 223, and an operatinghead 236, which has an operating part 236 a extending from the body 235in a truncated cone shape in which opposite radial sides thereof arepartially cut out to communicate with the hole of the body 235.

The spring holder 250 includes a cylindrical holder body 251, which isinclined toward a front end thereof which is open and has a pressureadjusting hole 254 adjacent to a rear end thereof, a plurality of ribs252, which protrudes from the front open end of the holder body 251 in aradial direction, and a plurality of holder channel slots 253, each ofwhich is grooved in an outer circumference of the holder body 251between the two adjacent ribs 252.

The pressure adjusting hole 254 of the holder body 251 is closed by theoperating head 232 or the operating part 236 a of the safety check valve230. As for the operation of the pressure adjusting hole 254, when animpact exceeding design pressure is applied in a completely closedstate, the oil pushes the operating head 232 or the operating part 236 aof the safety check valve 230 to flow out through the open slot 231 a orthe interior of the body 235 of the safety check valve 230.

A pressure limit is set depending on a size of the pressure adjustinghole 254. When the size of the pressure adjusting hole 254 is increased,resistible pressure limit is decreased. In contrast, when the size ofthe pressure adjusting hole 254 is decreased, resistible pressure limitis increased. The design pressure refers to pressure that can beabsorbed by the check valve. If the pressure limit exceeds the designpressure, the safety check valve 230 is operated.

The check valve 240 includes a check valve body 241, which has the shapeof a ring so as to be displaceable between the rear of the piston body221 of the piston 220 and the ribs 252 of the spring holder 250 and hasa plurality of ridges 241 a on an outer circumference thereof, and aplurality of channel forming protrusions 242, which protrude forwardfrom the check valve body 241 to form partitions.

The ridges 241 a protrude at a very low height in order to improve aproblem caused by tolerance, but are formed to be able to block thechannel by close contact with the inner circumference of the body 100regardless of the tolerance when being in close contact with the innercircumference of the body 100. The design pressure can be set byadjusting the number of ridges 241 a.

When an impact occurs, the check valve 240 is expanded outward by theoil introduced in a moment, thereby partially blocking the oil escapingthrough the channel slots 221 c of the piston 220. As a result, theimpact can be absorbed.

The bushing 310 is inserted into the sponge 320. The oil distributor 330is coupled to one end of the bushing 310 at one end of the sponge 320.

The bushing 310 has a hole in the middle thereof, and includes acylindrical front body 311, a guide body 312 in the rear of thecylindrical front body 311, and a seal fixing ring 313 protrudingforward from the front body 311.

The seal fixing ring 313 supports the interior of the oil seal 420, sothat it prevents the oil seal 420 from being contracted in spite oflong-term use.

The cover 410 has a hole in the middle thereof, and has a cylindricalshape so as not only to close the rear end of the body 100 in engagementwith the body 100 on an outer circumference thereof but also support thefront of the oil seal 420. Further, the cover 410 has a cover protrusionstep 414 protruding backwards.

As describe above, the oil seal 420 is not contracted thanks to the sealfixing ring 313 of the bushing 310 and the cover protrusion step 414,which are inserted into the oil seal at the front and rear of the oilseal 420 respectively.

Hereinafter, the operation of a door damper according to an exemplaryembodiment of the present invention will be described below.

The door damper of the present invention is mounted on the frame orhinge of a door through its case. when a door is opened, the returnspring 210 returns to push the piston 220, the oil flows to the holderchannel slots 253, passes between the ridges 241 a of the check valve240, and goes past the projections 222 a of the piston 220, and thenthrough the channel slots 221 c.

When the door is closed, the oil flows in the opposite way to theabovementioned direction. If the door is abruptly closed (within thedesign pressure), the check valve 240 is expanded to lower a height ofeach ridge 241 a. Thereby, the oil flowing along the outer circumferenceof the check valve 240 is nearly blocked by the ridges 241 a having thelow height. The channel forming protrusions 242 in front of the checkvalve 240 strongly come into close contact with the rear of the pistonbody 221, so that the channel can be narrowed to relieve an impact.

If the door is closed with a pressure limit exceeding the designpressure, the check valve 240 is expanded, and the operating head 232 orthe operating part 236 a of the safety check valve 230 is pushed.Thereby, the oil flows from the holder channel slots 253 into the springholder 250 and the piston 220, and then flows out of the safety channelgroove 221 b, so that the pressure within the pressure limit can bewithstood.

Although exemplary embodiments of the present invention have beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

The invention claimed is:
 1. A door damper comprising: a cylindricalbody, which is open on a first side thereof and has a bumper on a secondside side thereof; a return spring, which is inserted into the body; aspring holder, which supports the return spring; a piston, which isinserted into the spring holder; a check valve, which is installedbetween the spring holder and the piston; a piston rod, which is coupledto one side of the piston and protrudes outside the body; an oildistributor, which has the piston rod passing therethrough and is incontact with the piston; a sponge, which is in contact with the oildistributor, has the piston rod passing therethrough, and is fixed to abushing; and a cover, which covers the first side of the body togetherwith an oil seal contacting the bushing, wherein the piston includes asafety check valve therein, which is opened in cooperation with thecheck valve installed between the spring holder and the piston when apressure higher than a design pressure is applied.
 2. The door damperaccording to claim 1, wherein the piston has a shape of a cylinder inwhich a hole is formed, and includes a piston body at an upper portionthereof, an operating body formed integrally with the piston body andhaving an outer diameter less than that of the piston body, and aninserting body formed integrally with the operating body and having anouter diameter less than that of the operating body.
 3. The door damperaccording to claim 2, wherein the piston body includes a rod insertinghole at an upper end thereof, and at least one safety channel grooveformed around the rod inserting hole.
 4. The door damper according toclaim 3, wherein the piston body includes four through eight channelslots in an outer circumference thereof.
 5. The door damper according toclaim 2, wherein the piston body includes four through eight channelslots in an outer circumference thereof.
 6. The door damper according toclaim 1, wherein the spring holder includes: a cylindrical holder body,which is inclined toward a front end thereof which is open, and has apressure adjusting hole adjacent to a rear end thereof; a plurality ofribs, which protrudes from the front open end of the holder body in aradial direction; and a plurality of holder channel slots, each of whichis grooved in an outer circumference of the holder body between theplurality of ribs.
 7. The door damper according to claim 1, wherein thecheck valve includes: a check valve body, which has a shape of a ring soas to be displaceable between a rear of a piston body of the piston andthe plurality of ribs of the spring holder, and has at least one ridgeon an outer circumference thereof; and at least one channel formingprotrusion, which protrude forward from the check valve body to formpartitions.
 8. The door damper according to claim 1, wherein the safetycheck valve is made of material having strong elasticity, and includes acylindrical valve body, in an outer circumference of which an open slotis formed in a longitudinal direction, and an operating head that isformed in a truncated cone shape at one end of the valve body.
 9. Thedoor damper according to claim 1, wherein the safety check valveincludes: a cylindrical body, which is integrally formed with one end ofa inserting body of the piston, and has a hole so as to be able tocommunicate with the hole of the inserting body; and an operating head,which has an operating part extending from the body in a truncated coneshape in which opposite radial sides thereof are partially cut out tocommunicate with the hole of the body.
 10. The door damper according toclaim 1, wherein the bushing has a hole in a middle thereof, andincludes a cylindrical front body, a guide body in a rear of thecylindrical front body, and a seal fixing ring protruding forward fromthe front body.
 11. The door damper according to claim 1, wherein thecover has a hole in a middle thereof, includes a cylindrical shape so asnot only to close a rear end of the body in engagement with the body onan outer circumference thereof but also support the front of the oilseal, and a cover protrusion step that protrudes backwards.